Brand new here. I did a quick search of the forum but didn't see anybody with the same problem. I have a 2-story house built in the 70's. Top floor has a wood fireplace with a glass door. Bottom floor has a round portal into the chimney for what I'm guessing would be a pot belly stove hookup. I would like to cover up the lower floor chimney portal. The metal structure within appears to have venting around the inner flue. Can I just sawzall the metal that prodrudes from the wall, plug the hole, and put an access panel over the opening?